feat(remote-comms): Add Node.js e2e tests and fix shutdown handling

[sirtimid]

This PR adds comprehensive end-to-end tests for remote kernel communications in Node.js and addresses critical shutdown issues discovered during testing.

Changes

Testing Infrastructure:

• Added Node.js e2e tests for basic remote kernel connectivity, message passing, and OCAP URL handling
• Tests cover basic kernel-to-kernel communication through a libp2p relay server

Remote Communications Fixes:

• Fixed hanging libp2p.stop() issue by switching to connection abort strategy instead of full stop
• Made stopRemoteComms() safe to call when remote comms not initialized (returns early instead of throwing)
• Improved relay server configuration for better connection management (reduced hop timeout, disabled default limits)

Database Management:

• Added close() method to KernelDatabase interface for proper resource cleanup
• Implemented database close functionality for both Node.js and WASM SQLite implementations
• Tests now use in-memory databases (:memory:) to avoid file locking issues

Kernel Shutdown:

• Refactored kernel stop sequence to properly stop remote comms through platform services
• Fixed test cleanup to ensure kernels and databases are properly closed after each test
• Resolved hanging process issues during test suite execution

Technical Details

The main issue addressed was that libp2p.stop() could hang indefinitely, preventing clean kernel shutdown. The solution involves:

1. Aborting all active connections instead of calling libp2p.stop()
2. Clearing the libp2p instance reference to allow garbage collection
3. Ensuring proper cleanup order: queue → command stream → remote comms → platform services

Testing

• All existing tests pass
• New e2e tests verify basic remote kernel communication functionality
• Tests run sequentially to prevent resource conflicts

---

Note

Adds Node.js e2e remote-comms tests, shifts libp2p shutdown to connection aborts, makes stopRemoteComms safe if uninitialized, refactors kernel stop order, and introduces KernelDatabase.close().

• Remote communications & shutdown:
  • ConnectionFactory.stop() now aborts all connections (no libp2p.stop()), clears inflight dials, and logs hangups; tests updated accordingly.
  • Kernel stop() reordered: wait for queue → end command stream → stop remote comms via platform services → terminate workers.
  • Platform services (browser/node): stopRemoteComms returns early if not initialized; related tests updated.
  • Relay config tweaks in packages/cli/src/relay.ts: disable default reservation limits and reduce hopTimeout; removed unused protocol handler; added connection/discovery logging.
• Node.js E2E tests:
  • New end-to-end tests for remote kernel connectivity and OCAP URL messaging via a local relay; adds test/vats/remote-vat.js and test/make-test-kernel.ts.
  • CI script passes through args to e2e runner.
• Kernel store:
  • Add close() to KernelDatabase; implement in SQLite (Node/WASM) and add tests.
• Misc:
  • Add dependencies for tests/runtime (@endo/eventual-send, @endo/marshal, @libp2p/interface); adjust coverage thresholds.

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[FUDCo]

LGTM. This looks like it potentially might address one of the things I'm trying to puzzle out!